Can We Agree On A Battery Level?

[JohnL]

The typical Lipo has a discharge curve similar to the graph bellow. As you can see when the voltage gets to a certain level the drop off is quite steep. This means that you can find yourself on the ground before you even know it. Discharging a Lipo to 3.5V per cell is not really bad, just as long as you let it get to room temperature before recharging. The worst you can do to a Lipo is charging it while hot, charging at a rate higher than 1C ( 1X rated discharge capacity) and drawing more than it's maximum discharge rate longer than the rated time. Now, I have stored Lipos fully charged for months at a time without adverse effect. I never storage charge my Lipos, I regularly discharge them to their minimum and some times bellow. In a few occasions, I have run a pack flat which I have brought back to life by doing NiCad charge until the voltage is above 3V then switching to Lipo balance.Most Lipo cgargers will not charge if cells are bellow 3V. I don't know the quality of the H batteries so I can't comment,I am basing my experience with Venom battery brand which are very tough and take abuse well. So , what you need to do is find the curve on your Lipos by trial and error so that you know exactly when to land and still get as much out of them as you can. Keep in mind that Yuneec does not make batteries, they purchase them from vendors, put them in their case and brand them. So there is no way to know where they come from and how consistent they are, so not all your batteries are going to behave the same. Hope this helps some.]

You beat me to it, Charlie. These curves are very helpful and explain a lot. Great post!

 

[JohnL]

Personally, I would be on the ground at 14Volts (3.5 Volts/cell) This is an "under load" measurement. So obviously that would climb without load.
I have always used voltages on my OSD's rather than percentage, so for my current 6s packs I make sure I'm on the ground at no lower than 21Volts.

That's about right, maybe even a little conservative. I'm not sure you would even be using 80% of your capacity here, but of course one also has to consider discharge rate and vehicle type/load. My own personal rule of thumb is to try and land before I hit about 3.4V/cell, and always try to never go below 3.2-3.3V/cell. I've ruined batteries by consistently taking them to 3.0-3.1V

[Of course, every pack is different and these proprietary units for the H have little real world use yet. C rating effects voltage readings under load. Does anyone know the C rating of these packs yet?

I don't think anyone has stripped off the hardcase plastic shell yet. Clearly right now there's no one who wants to ruin this **** proprietary battery at the moment. I think it's safe to assume it's at least 25C given that there are six motors to power plus electronics plus camera equipment. I'd bet it's more like 50C IMHO.

 

[Yurs Truly]

Looks like I need a degree in chemistry and/or electrical engineering along with a pilot's license to fully understand this hobby. Ugh.

I hope someone comes up with a number I can land at and not ruin my battery because this is very confusing.

just follow the "batterychart"... that is the bible of lipos state of charge that we are using for more than 6yrs courtesy of the battery guru from rcgroupsdotcom

 

[JohnL]

The worst you can do to a Lipo is charging it while hot, charging at a rate higher than 1C ( 1X rated discharge capacity) and drawing more than it's maximum discharge rate longer than the rated time. Now, I have stored Lipos fully charged for months at a time without adverse effect. I never storage charge my Lipos, I regularly discharge them to their minimum and some times bellow.

Charlie, you have provided great information to the thread but I have to disagree with you on this one. LiPos become very unhappy if left at full charge over long periods of time. I know because I'm speaking from my own experience here and that of my other RC colleagues. If I can, I never full charge my batteries unless I know I will fly the next day. At the end of the day when back at home and after battery cool down, I always recharge back to a safe "Storage Charge" level unless I know I will be flying again the very next day.

YMMV and I guess you've been lucky by having no adverse effects on your personal store of batteries. Not trying to criticize you here either as you clearly seem to be an experienced RC guy. Just throwing in my 0.02€ in.

 

[n3srj]

Ask a dumb question, what's the charge time?

Brand new out of the box battery took an hour for me..

 

[Andyzonk]

Back when LiPos first came out they were sold as being better than NiCad because they 'held' their charge and gave more power. I made the Mistake of always fully charging them before storage - Fatal - wrecked the lot of them in a very short time.

 

[JohnL]

Ask a dumb question, what's the charge time?

Brand new out of the box battery took an hour for me..

Remember that the battery probably came shipped from the factory at about 65-70% charge. Also assume that the pathetic little charger from Yuneec is only charging at about 0.5C as compared to the much more normal 1C (heck, a lot of RC folks charge at 2C or more). I've heard that a fully discharged Typhoon-H battery can take up to two hours to charge. Can any of you pilots who are lucky enough to have Typhoon-H's in their hands confirm this?

 

[n3srj]

Remember that the battery probably came shipped from the factory at about 65-70% charge. Also assume that the pathetic little charger from Yuneec is only charging at about 0.5C as compared to the much more normal 1C (heck, a lot of RC folks charge at 2C or more). I've heard that a fully discharged battery can take up to two hours to charge. Can any of you pilots who are lucky enough to have Typhoon-H's in their hands confirm this?

Took 1.5 hr on a "used till alarm" battery to recharge 1st time.. 2nd time 1.75 hr will report #3 when it happens on that battery.

 

[JohnL]

Back when LiPos first came out they were sold as being better than NiCad because they 'held' their charge and gave more power. I made the Mistake of always fully charging them before storage - Fatal - wrecked the lot of them in a very short time.

Hey Andy. I did even worse during my first year of home building and flying of MR's. I would regularly fly my quads/hexes util I just about 100% discharged my batteries. To add insult to injury sometimes I would even charge them back up before they were fully cooled down. Suffice to say I must have assassinated over a dozen LiPos before I got a clue.

 

[Andyzonk]

Hey Andy. I did even worse during my first year of home building and flying of MR's. I would regularly fly my quads/hexes util I just about 100% discharged my batteries. To add insult to injury sometimes I would even charge them back up before they were fully cooled down. Suffice to say I must have assassinated over a dozen LiPos before I got a clue.

Yes, Been there. I would fly my Helicopters until they had no more Lift, then straight back on the charger. I think I got about 10 flights per battery. I figured - Crap ebay battries -

 

[JohnL]

Yes, Been there. I would fly my Helicopters until they had no more Lift, then straight back on the charger. I think I got about 10 flights per battery. I figured - Crap ebay battries -

LOL! Apparently in this hobby/sport/profession there is only ONE way to learn...the hard way.

 

[imu.ghost]

Took 1.5 hr on a "used till alarm" battery to recharge 1st time.. 2nd time 1.75 hr will report #3 when it happens on that battery.

Thanks, good to know!

 

[DroneClone]

Today when coming back home from a distance test with my new FPVLR antenna I had a strong headwind (20-22 MPH) and my low battery warning came on while I was still about 2,000' from home. I checked and the display showed voltage at 14.6v which is odd because the other day the warning came on while hovering near home at 14.3v. I was not in a good landing location so came down low and continued flying home at a slower speed (something like 6-7 MPH, if I recall correctly), while continually watching the voltage reading. Oddly, the voltage did not drop any further than 14.6v over the next few minutes and I then landed about 100' from where I was standing as I didn't want to use battery power to climb over some trees between me and that landing spot. After I shut down the motors voltage reading was 14.9V which I think is an okay level for battery life.

Based on this experience, it seems that the low battery warning will come on at a higher voltage reading when flying hard vs. hovering.

I chatted with Tim at Yuneec about battery voltage readings earlier. I'll address some things he shared (all consistently in 4 cells so that it's clearer):
1. Should not store battery fully charged for more than 72 hours. Best to store at 15.4v.Not True, 10 days is acceptable. Then discarge to 60%
2. Over discharging repeated to 13.6v-14.0v will decrease battery life True
3. Operating drone and draining battery down to 14.6v "is not bad" but 15.2v "is preferred" 14.8 to 15.0 is good

Since there is some voltage sag with motors running, I think I'll target somewhere around 14.7v-14.9v with motors running when landing. Not advice for others, make your own judgement.call on this.

 

[HarveyC]

Ask a dumb question, what's the charge time?

I haven't timed it but it varies depending on how depleted the battery is. Simon in his first flight video flew it until he had the first battery warning and then reported the charging time. I think he said either 2 hours or 1:50, check the video on YouTube

 

[charliehorse]

Could it be that the H system knows how far out you are. Then raises the voltage warning to give you more "reserve" to get home inside a safe voltage level. Hence the different voltages.

 

[imu.ghost]

I haven't timed it but it varies depending on how depleted the battery is. Simon in his first flight video flew it until he had the first battery warning and then reported the charging time. I think he said either 2 hours or 1:50, check the video on YouTube

Yes, 2 hours to fully charge one battery. Kind of long!

 

[Yurs Truly]

guys don't make it complicated.. if u guys don't want to use the voltage and the chart, just use the battery bar .. if you have ONE bar left, its time to land, that approximate 25% left on the battery ... don't be mislead by false advertisement of all drone manufacturers concerning about batteries usage times.. that is usually based on 100% drain with no wind or minimum atmosphere resistance... the always rule of thumb is 80% usage so that could be the minutes of advertised time, % on your battery bar, and or voltage ....

 

[Tecneek]

This is not totally accurate as not all packs are equal, but it is close enough.
Print it and tape it to the back or your ST-16
View attachment 627

Great! Now all I need to figure out is what are the best settings, and best speed to fly, then trying to conserve to make it back home, then I will be able to determine how many feet I can travel per certain voltage amount. I noticed return to home takes the longest route. I would say when you see the bird, to begin to bring her down in a straight path towards you.

 

[billycastro]

My batteries got very low. Brought it down to a few feet off the ground to take a picture and it attacked me! Think error code engine 5 came up. Anyone have any similar incidents? Yuneec had no answer and has not contacted me back yet. bc

 

[billycastro]

Let my batteries get low. Brought it down to a hover about 3 feet off the ground to take a picture. Out of nowhere it flew right at me. Crashed in front of me, had to stop it with my foot. Error code came up " engine error 5". Yuneec has not responded. Yes before you ask, was in angle mode. Anyone have any similar incidents? bc